Polyalkoxyacetals or polyalkoxy ketals and the sulfur analogues



United States Patent on a itate Patented Nov. 10, 1959 POLYALKOXYACETALSR POLYALKOXY KE- TALS AND THE SULFUR ANALOGUES John W. Copenhaver, ShortHills, N.J., assignor to General Aniline & Film Corporation, New York,N.Y., a corporation of Delaware 1 No Drawing. Application December24,1956 Serial N0. 630,019

4 Claims. or. 260-609) The invention here presented is a new synthesisfor the preparation of polyalkoxy acetals and ketals and the sulfuranalogues thereof by a simple and inexpensive procedure whereby the costof'these compounds is very substantially reduced.

There are many reactions which will yield valuable and useful substancessuch as dyestulfs,pharmaceuticals, synthetic resins and the like,utilizing such polyalkoxyacetals and ketals, which have beencommercially unfeasible be- US. 2,165,962, US. 2,487,525, US. 2,561,307and the like, due to the needfor appropriate substituents on theunsaturated carbons of the a ti-unsaturated ether intermediates, saidintermediates thereby yielding complicated, diflicult, uncertain andexpensive synthetic problems.

According to the present invention it is found that in the'presence ofan acid catalyst, an equilibrium exists between an acetal, or a ketal,and the corresponding alcohol and c p-unsaturated ether, according tothe following equations:

R'GH=o.-0R ROH OR I By removing the alcohol from the equilibriummixture, the equilibrium can be forced in the direction of thea,;3-unsaturated ether by any desired amount, and it is then found thatthe resulting a ti-unsaturated ether will react with other portions ofthe acetal or ketal to form a polyalkoxy acetal, or polyalkoxy ketal.This reaction removes the vinyl ether from the equilibrium mixture shownand further favorably influences the shift inequilibrium. The readilyavailable acetals and ketals can be used as one reactant and as theprecursor of the second reactant, as outlined in the following equation:

(1) CH30H OR 2 ROH+ CHFCHOR omcmom, nCHFOHQR on on omon omcmoa o Rom (mLit (in i t: he

The-reaction is not limited to the oxygen containing compounds butapplies similarly to the sulfur analogues such as the mercaptals andmercaptols, as shown in the following equation:

however difiiculty is encountered and a more potent catalyst is used,such compositions as solutions of aluminum chloride or boron trifluoridein non-aqueous, anhydrous solvents such as ethyl or methyl chloride maybe used. The reaction is desirably conducted at a mildly elevatedtemperature sufiicient to distill out the alkanol' or alkanethiolcomponent which is split out the reaction. The alkanol or alkanethiolisremoved'sometimes in the form of an azeotrope of the acetal' or theket'al and ,the cleaved methanol, or ethanol, or propanol, or butanol,

or mercaptan, or the like. It will be observed that the removal of thealcohol by distillation, or evaporation, permitsthe--reaction-to"proceed by a shifting of the equilibrium. It mayfurther be noted that this distillation can usually be done atatmospheric pressure,but in some instancesthe boiling point of thealcohol or other material is too low for satisfactory conduct of theremainder of the reaction, in which case the distillation may beconducted under pressure. Alternatively, in some instances, the boilingpoint of the alcohol is high so that the alkanol or alkanethiol cannotbe removed satisfactorily at atmospheric pressure or may lead tobreakdown at such elevated temperatures to yield undesired sidereactions. In such-case, the distillation may be conducted at reduced"pressure. carry the reaction to complete conversion, since, whenFurthermore, it is usually preferable not to ,3 a the reaction iscarried beyond about 75' percent, the material tends to resinify and toyield higher boiling, undesired products from side reactions.

Thus the basic procedure involves a shift of the equilibrium in thedesired direction by removal of the resulting alcohol or mercaptan topermit, under acid conditions, condensation of a portion of theresulting aft-unsaturated ether with a portion of theoriginal acetal orketal to yield the desired polyalkoxyacetal, polyalkoxyketal,polyalkylthiomercaptals (thioacetals) and polyalkylthiomercaptols(thioketals The following examples are offered as indicating the bestway now known of practicing the invention but are not intended to limitthe scope of the claims in any way.

EXAMPLE 1 Preparation 1,1,3-trimeth0xy butane from dimethyl acetal Thefollowing reaction occurs according-to this. example ZBF 2GH3OH(OCH3)1OH3CHQCH2CH(OOH3)3 CHgOH OCH; The following materials were put togetherin the orderand in the quantities listed to yield the product shown.

360g. (4 moles) of dimethyl acetal and 4 ml. of boron fluoride etheratewas charged to a 1000 ml. flask attached to a packed fractionatingcolumn.

The reaction mixture was heated to reflux and The fraction. boiling at57 to 627 C./-20 mm. was re fractionated at atmospheric pressure andboiled at- 152 to 154 C., and had n 1.4010 and d4 0.9163. Authentic1,1,3-trimethoxy butane boils at 154 C.,.and has n 1.4010'and 11 0.9145.Theidentity-ofi the product was confirmed by conversion tothe2,4-dinitrophenyl hydrazone of crotonaldehyde, which is the prod.-

uct formed from authentic 1,1,3-trimethoxy butane;-

under identical reaction conditions.

EXAMPLE 2 Preparation of 1,1,3-tri-thioelhyl butane The followingreaction occurs according to this example:

CH3CHCH2CH(SC':H0: 1 25 11 The following materials were put together inthe order and in the quantities listed to yield the product shown.

75 g. (0.5 mole) diethyl mercaptal and 0.5 ml. of boron fluorideetherate was charged to a 150 ml. flask attached to asmall packedfractionating column heated to reflux and 11 ml. ethyl mercaptan boilingat 35 C./760 mm. wasremoved as rapidly as possible. The boron fluorideetherate was neutralized with sodium methylat'e and distillationcontinued to yield 18 g. unreacted' diethyl mercaptal and 13 g.1,1,3-tri-thioethy1 butane boiling mm., n 1.5210.

at 159 C./17'

4. Analysis theory.-C, 50.36%; H, 9. 30%; S, 40.33%;

Found: C, 50.38%; H, 9.16%; S, 40.43%.

EXAMBLE 3 Preparation of 1,1,3-trieth0xy-2-ethyl hexane The followingreaction oecursaccording to this exe ample:

The following-materials .were;put togetherrin the order and in thequantities listed toyield' the product shown.

435 g. (3 moles) diethyl'butyral and" 2.2 ml. of boron fluoride etheratewas charged to a 100.0 ml. flask attached to a fractionat-ingcolumn andheated to reflux.

27 g.- (0.5 8- mole) ofethanol. was removed as rapidly as thetemperatureat the headfofi the column'could' be maintained at 78 C. Theboron fluoride etherate wasneutralized with ethanolamineand distillationcontinued. After removing: more ethanol and the unreacted diethylbutyral, there was obtained 68 g. of 1;1:,3:-triethoxy.-2-ethyl. hexane,B.P-. 94

mm., n '1.42-72andsmaller amOuntsOf higherhQmologues boiling over. a.rangev up. to 192 (ll-5 The 1.,1;3-triethoxy-2-ethy17 hexane. wascharacterind by analysiszTheoryz'C, 68.24%;-.H;,12.27.-%. Found: C,-69.14%;.H; 12.22%.

Reaction with. 2,4-dinitrophenyl; hydrazine in'theusual manner gave-the=2,4dinitrophenyl. hydrazone of Z-ethyl- 2-hjexanal;,M..P. 123 C.

AnaZysin-Theory: C, 5.4;9.0.%;:'H-,, 5.9.2%.; N, 18.29%. Found: C,54;94%'; H;, 5.89%; N, 17.96%.

The reported melting point-for theiderivative is 122C. (Compt. rend.196, 278 (1933) and 124125 C. Chem. and Ind. 52, 519 1933.)

Thus the reaction and process of the present invention produce awiderange of products which are valuable for a wide range of subsequentorganic reactions for the manufacture of dyestuffs, pharmaceuticals,synthetic resins and the like.

While there are above disclosed but alimited number of embodiments ofthe process of the invention, it is possible to provide still' otherembodiments without departing'from the inventive concept hereindisclosed, and it is therefore. desired that only such limitations beimposedupon. the appended claims as are stated therein or re quiredibythe prior art.

The invention claimed is:

1; Themethod of making compounds selected from the. group consisting ofalkoxy substituted acetals and ketals and the sulfur analogues thereofand represented by theformulawherein R represents a member of the groupconsisting of hydrogen and alkyl, R represents a member of the groupconsisting of hydrogen and alkyl', R represents a lower alkyl and Xrepresents a chalkogen having an atomic Weight less than 33, whichcomprises heating to reflux in the presence of a small amount of boronfluowherein R, R and R" and X are as defined above, while removing bydistillation any compound of the formula R"-XH formed.

2. The process of producing 1,1,3-trimethoxybutane which comprisesheating to reflux, in the presence of a small amount of boron fluoride,dimethyl acetal, while removing by distillation during said heating stepany methyl alcohol formed, whereby there is produced said1,1,3-trimethoxybutane.

3. The method of producing 1,1,3-tri-thioethyl butane which comprisesheating to reflux, in the presence of a small amount of boron fluoride,diethyl mercaptal, while removing by distillation during said heatingstep any ethyl mercaptal formed, whereby there is produced said 1,1,3-tri-thioethyl butane.

5 any ethanol produced, whereby there is 1,1,3-triethoxy-2-ethyl hexane.

References Cited in the file of this patent UNITED STATES PATENTS TurnerDec. 29, 1936 Mochel Jan. 28, 1941 Paul at al. Dec. 16, 1952 OTHERREFERENCES Killian et a1.: Jour. Amer. Chem. Soc., vol. 57 (1935),

obtained the said UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 2312,4168 November 10, 1959 John W; Copenhaver Column 2,lines 36 to 38 for that portion of the formula reading CH CHCH cmsc' Hread CH CHCH cmsc H a $0 11 SC2H5 Signed and sealed this 4th day ofApril 1961.,

(SEAL) Attest: ERNEST W. SWIDER )QX EEK ARTHUR w. CROCKER AttestingOfficer Acting Commissioner of Patents [UNITED STATES PATENT. OFFICECERTIFICATE OF CORRECTION Patent No. 2 9l2 -468 November 10 1959 John WCopenhaver It is hereby certified that error appears in the abovenumbered patent requiring, correction and that the said Letters Patentshould read as corrected below. I a

Column 6 line 3 for "mercapta.l read butyral Signed and sealed this 10thday Qf April 1962,

5 EA L) Attest:

ERNEST W. SWIDER DAVID L, LADD Attesting Offiel' Commissioner of Patents

1. THE METHOD OF MAKING COMPOUNDS SELECTED FROM THE GROUP CONSISTING OFALKOXY SUBSTITUTED ACETALS AND KETALS AND THE SULFUR ANALOGUES THEREOFAND REPRESENTED BY THE FORMULA